The MRI apparatus is an image diagnostic apparatus which magnetically excites nuclear spins of an object set in a static magnetic field with an RF (radio frequency) signal having the Larmor frequency and reconstructs an image based on MR (magnetic resonance) signals generated due to the excitation.
In the MRI apparatus, eddy magnetic fields which arise due to the generation of gradient magnetic fields are tried to be reduced since eddy magnetic fields adversely affects affect imaging. Now, the technology to use an ASGC (Actively Shielded Gradient Coil) as a coil for gradient magnetic fields in order to suppress eddy magnetic fields has become mainstream. The ASGC is the gradient coil which has a cylindrical shield coil to suppress a leak magnetic field, outside of a cylindrical main coil for forming respective gradient magnetic fields in the X-axis, the Y-axis, and the Z-axis directions respectively.
It is an object of the present invention to provide a magnetic resonance imaging apparatus and a magnet for a magnetic resonance imaging apparatus which can form desired gradient magnetic fields with a simpler configuration.